Japanese Patent Publication No. 23,394/1971 discloses that aminopyrimidines represented by the following formula ##STR1## wherein A represents an alkylene group having up to 16 carbon atoms, or a lower alkylene group substituted by an amino group or a C.sub.2-5 acylamino group, N represents H, Na, K, NH.sub.4, Mg, Ca or an organic basic ammonium salt, and n is a value equal to the atomic valency of M,
have interesting therapeutic activity, particularly as an anti-melanchoric agent and psychoanaleptic agent in the field of psychosis.
Japanese Patent Publication No. 22044/1976 discloses that dichloro-lower aliphatic carboxylic acid salts of 2-isopropylaminopyrimidine, such as 2-isopropylaminopyrimidine dicloroacetate, are useful as a therapeutic agent for a neurological disease.
Japanese Laid-Open Patent Publication No. 00477/1977 (Patent Publication No. 28548/1984) discloses that 2-isopropylaminopyrimidine phosphate is useful as a therapeutic agent for a neurological disease.
Japanese Patent Publication No. 157575/1979 discloses a process for producing 2-chloropyrimidine in a high yield. A working example in this patent publication describes the preparation of 2-chloropyrimidine in a yield of 69%.
Japanese Laid-Open Patent Publication No. 393/1980 discloses a process for producing 2-isopropylaminopyrimidine in a high yield. A working example of this patent publication describes the preparation of 2-isopropylaminopyrimidine in a yield of 60%.
Japanese Laid-Open Patent Publication No. 122768/1980 discloses that a hydroxy derivative of 2-isopropylaminopyrimidine represented by the following formula ##STR2## wherein A.sup.4, A.sup.5 and A.sup.6 each represent H or OH, and at least one of them represents OH,
is useful in the field of nerve regeneration and for treatment of myodystrophy.
Japanese Laid-Open Patent Publication No. 145670/1980 discloses that 2-isopropylaminohalogenopyrimidines represented by the following formula ##STR3## wherein A.sub.4 ', A.sub.5 ' and A.sub.6 ' each represent H or a halogen atom, and at least one of them is a halogen atom,
are useful for treatment of various neurological diseases and myodystrophy.
Japanese Laid-Open Patent Publication No. 145,671/1980 discloses a process for producing a hydroxy derivative of 2-isopropylaminopyrimidine.
Japanese Laid-Open Patent Publication No. 151,571/1980 discloses that 2-isopropylamino-5-halogenopyrimidines are interesting in the treatment of neurological diseases.
Japanese Laid-Open Patent Publication No. 10177/1981 discloses a process for producing 2-isopropylaminopyrimidine substantially in a quantitative yield by aminolyzing 2-methylsulfonylpyrimidine with isopropylamine.
Japanese Laid-Open Patent Publication No. 26880/1981 discloses a process for producing 2-isopropylaminopyrimidine which comprises reacting bis(isopropylguanidine) sulfate with 1,1,3,3-tetraethoxypropane.
Japanese Laid-Open Patent Publication No. 90,013/1981 describes a therapeutic agent for myodystropy, myopathy, muscle rigidity and/or dysfunction of neuro-muscular transmission comprising substituted derivative of pyrimidine or its therapeutically acceptable salt or its metabolite as an active ingredient. However, it merely discloses various salts such as an orthophosphate, of 2-isopropylaminopyrimidine as an active compound.
Japanese Laid-Open-Patent Publication No. 65873/1986 discloses that 2-piperazinopyrimidine derivatives of the following formula ##STR4## wherein R.sup.1 is H or aralkyl, and Y is a divalent organic group defined in the claim of this patent publication,
are useful as a herbicide for paddies and upland farms.
The present inventors previously provided a novel therapeutic agent for neurological diseases comprising a specified 2-piperazinopyrimidine derivative or its pharmaceutically acceptable salt (International Laid-Open No. WO87/04928).